1# Global Time Zone Database (global-tz) 2 3The Global Time Zone Database contains the history of how local time has changed around the world. 4It is derived from data in the [IANA Time Zone Database](https://github.com/eggert/tz). 5For many years this information could be reliably obtained from the IANA repository. 6In recent years however, the data available by default from the IANA repository has been reduced. 7This repository primarily exists to reinstate the data that has been effectively removed. 8 9For more info, please see the project home page: 10https://github.com/JodaOrg/global-tz 11 12The original README is included below. 13 14----- 15 16README for the tz distribution 17 18"Where do I set the hands of the clock?" -- Les Tremayne as The King 19"Oh that--you can set them any place you want." -- Frank Baxter as The Scientist 20 (from the Bell System film "About Time") 21 22The Time Zone Database (called tz, tzdb or zoneinfo) contains code and 23data that represent the history of local time for many representative 24locations around the globe. It is updated periodically to reflect 25changes made by political bodies to time zone boundaries, UTC offsets, 26and daylight-saving rules. 27 28See <https://www.iana.org/time-zones/repository/tz-link.html> or the 29file tz-link.html for how to acquire the code and data. 30 31Once acquired, read the leading comments in the file "Makefile" 32and make any changes needed to make things right for your system, 33especially when using a platform other than current GNU/Linux. 34 35Then run the following commands, substituting your desired 36installation directory for "$HOME/tzdir": 37 38 make TOPDIR="$HOME/tzdir" install 39 "$HOME/tzdir/usr/bin/zdump" -v America/Los_Angeles 40 41See the file tz-how-to.html for examples of how to read the data files. 42 43This database of historical local time information has several goals: 44 45 * Provide a compendium of data about the history of civil time that 46 is useful even if not 100% accurate. 47 48 * Give an idea of the variety of local time rules that have existed 49 in the past and thus may be expected in the future. 50 51 * Test the generality of the local time rule description system. 52 53The information in the time zone data files is by no means authoritative; 54fixes and enhancements are welcome. Please see the file CONTRIBUTING 55for details. 56 57Thanks to these Time Zone Caballeros who've made major contributions to the 58time conversion package: Keith Bostic; Bob Devine; Paul Eggert; Robert Elz; 59Guy Harris; Mark Horton; John Mackin; and Bradley White. Thanks also to 60Michael Bloom, Art Neilson, Stephen Prince, John Sovereign, and Frank Wales 61for testing work, and to Gwillim Law for checking local mean time data. 62Thanks in particular to Arthur David Olson, the project's founder and first 63maintainer, to whom the time zone community owes the greatest debt of all. 64None of them are responsible for remaining errors. 65 66----- 67 68This file is in the public domain, so clarified as of 2009-05-17 by 69Arthur David Olson. The other files in this distribution are either 70public domain or BSD licensed; see the file LICENSE for details. 71